In order to manufacture a cord yarn with thin design, great tenacity and excellent dimensional stability, various methods such as braiding, knitting using a needle, covering, simple twisting or the like have been widely used. However, because the structure not delicate, the cord yarn made by the above methods has high porosity, and a product formed with several strands has very low roundness.
Therefore, such a cord yarn has bad specific strength and a wide and flat shape, and its section is flattened more if a force is applied thereto.
In addition, Korean Unexamined Patent Publication No. 20-1998-0065555, published on Dec. 5, 1998, discloses a structure of a tire cord yarn, which however is different from a cord yarn of the present disclosure in which a plurality of filaments are twisted appropriately.
Moreover, Korean Patent Registration No. 10-0846197, published on Jul. 14, 2008, discloses a cord yarn supplying device for an embroidering machine and a cord yarn sealing method, which is also different from a cord yarn of the present disclosure in which a plurality of filaments are twisted appropriately.